Intelligent hubs are becoming widely deployed in networks to provide network connectivity to access devices. Hubs that provide access into the network allow the distribution of access policies and connectivity to occur close to the end system attachment.
At the same time, network-level routers are being deployed on a large scale to connect together the distributed hubs. In the past, this network service was provided by centralized router devices, as shown in FIG. 1A. However, as the centralized router's bandwidth and number of physical network interfaces become saturated, it is costly to add incremental distributed service. Once at capacity, it is necessary to add another centralized multi-port router even if the expansion only requires one new LAN to be attached--i.e., increments to the LAN access ports are done in large step functions.
To allow more scaleability, the router functions have been integrated into distributed hubs. As shown in Fig. 1B, this essentially "pushes" routing functionality out to the point where users gain physical connectivity into the network. In addition, these distributed routers can allow greater network access into a centralized router by off-loading the routing functions (FIG. 1C).
As the routing functionality pushes out and is more widely deployed, it places a tremendous strain on the configuration and control of these distributed devices. Also, because hubs provide for access by many LAN technologies, the router in a hub has to have support for a wide range of network connectivity in the same chassis. Furthermore, the number of access ports can vary from one or two, to several hundred, since these ports provide the connectivity to end users of the network.
To be able to implement routing services in these distributed hub and network devices, the architecture must be extremely flexible, scaleable, and adaptive to different hub configurations and chassis, and be able to support a variety of present and future protocols. Also, the architecture needs to provide a high degree of manageability since the operation and control of routing in these distributed hubs will be substantially more difficult due to the sheer number of these devices in a network and due to the variation of technology integrated in the hub/router.